Transient Voltage Detection Circuit for Automotive ESD Protection
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Solution Overview
Problem
Electronic systems are vulnerable to system-level transient noise such as EMI, ESD, and EFT, which can cause voltage undershoot or overshoot, leading to system malfunctions and safety issues, particularly in automotive on-board systems, where existing ESD protection circuits are inadequate in detecting and responding to voltage undershoot.
Innovation Solution
A transient voltage detection circuit is designed with PMOS and NMOS transistors, capacitors, and parasitic diodes to detect voltage changes on high and low voltage lines, using a judge module to generate judgments for selective protective actions, such as rebooting or shutting down the system, effectively addressing both undershoot and overshoot conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ESD protection circuits are used, then component-level ESD reliability is improved, but system-level transient voltage detection capability deteriorates
Solution Approach 1:
The invention divides the protection system into two independent parts: traditional ESD protection circuits for component-level protection and a new detection circuit for system-level transient voltage detection. This segmentation allows each part to specialize in its function without interfering with the other, resolving the contradiction between maintaining ESD protection while adding detection capability.
Solution Approach 2:
The invention introduces an intermediary detection circuit that monitors transient voltages on power supply lines and triggers protective actions. This intermediary component bridges the gap between the power supply system and the protected circuits, enabling system-level detection without requiring changes to the traditional ESD protection architecture.
2Object-affected harmful factors
If additional discrete components like TVS or varactor are added, then voltage overshoot protection is improved, but response to voltage undershoot deteriorates
Solution Approach 1:
The invention designs a universal detection circuit that can detect both voltage overshoot and undershoot conditions. Unlike traditional TVS or varactor components that only clamp overshoot voltages, this detection circuit monitors both directions of voltage deviation and triggers appropriate protective actions for either condition, making the system equally effective against both types of transient disturbances.
Solution Approach 2:
The invention implements a feedback mechanism where the detection circuit continuously monitors power supply voltage and triggers protective actions based on detected transient conditions. The feedback loop enables the system to respond dynamically to both overshoot and undershoot events, adjusting its protective response based on the actual voltage condition detected.
3Difficulty of detecting and measuring
If ESD detection circuit is added, then transient voltage detection is improved, but system complexity increases
Solution Approach 1:
The invention merges the detection function with existing power supply distribution networks and protected circuits. By utilizing existing power lines and integrating the detection circuit into the current system architecture, the invention avoids adding completely separate monitoring systems, thereby reducing overall system complexity while maintaining effective transient voltage detection capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The circuit effectively detects transient voltages and triggers protective actions, ensuring system stability and safety by differentiating the severity of voltage changes, allowing for timely responses to both undershoot and overshoot events, thus enhancing the reliability of electronic systems.
Implementation Method 1
A parasitic diode is formed between the drain electrode and the bulk electrode of the PMOS. When a transient voltage occurs on the high voltage line, the PMOS is in an off-state, and in the mean time the capacitor discharges through the parasitic diode to the high voltage line
Implementation Method 2
When a transient voltage occurs on the high voltage line, the PMOS is in an off-state, and in the mean time the capacitor discharges through the parasitic diode to the high voltage line, such that a voltage level of the detection node is lowered
Data Source
AI summary
The invention discloses a transient voltage detection circuit suitable for an electronic system. The electronic system includes a high voltage line and a low voltage line. The transient voltage detection circuit includes at least one detection circuit and a judge module. Each detection circuit includes a P-typed transistor and/or an N-typed transistor, a capacitor and a detection node. The transistor is coupled with the capacitor, and the detection node is located between the transistor and the capacitor. The judge module is coupled to each of the detection nodes. The judge module generates a judgment according to voltage levels of the detection nodes. Accordingly, the transient voltage detection circuit is formed. The electronic system may selectively execute a protective action according to the judgment.